1. Field of the Invention
This invention relates to a cartridge for accommodating therein dry-type chemical analysis films each having a layer containing a reagent, which will undergo a chemical reaction, a biochemical reaction, an immune reaction, or the like, with a specific biochemical substance contained in a liquid sample, such as blood or urine, and will thereby give rise to a change in optical density, such that the dry-type chemical analysis films can be taken out of a take-out opening one after another.
2. Description of the Prior Art
Recently, dry-type integral multi-layer chemical analysis films (also referred to as multi-layer chemical analysis elements) were developed for use in systems designed for performing quantitative analyses, with which systems the amounts or activity values of specific chemical constituents contained in droplets of liquid samples spotted onto the dry-type chemical analysis films or the amounts of specific physical constituents contained in the droplets of the liquid samples, are determined. Also, filter paper type of test pieces have been proposed, and single-layer or multi-layer test pieces have been obtained by improving the filter paper type of test pieces. Some of them have been used in practice.
In order to use a dry-type chemical analysis film in the quantitative analysis of a chemical constituent, or the like, contained in a liquid sample, a droplet of the liquid sample is put on the dry-type chemical analysis film. Specifically, in cases where the dry-type chemical analysis film has a spreading layer, the droplet of the liquid sample is put on the spreading layer of the dry-type chemical analysis film. In cases where the dry-type chemical analysis film has no spreading layer, the droplet of the liquid sample is put directly on the reagent layer of the dry-type chemical analysis film. The liquid sample is then kept at a predetermined temperature (i.e., incubated) for a predetermined time in an incubator, which causes a color reaction (i.e., a coloring matter generating reaction or a discoloration reaction of an indicator dye). The dry-type chemical analysis film is then exposed to light having a wavelength, which is selected in advance. The selection of the wavelength depends on the specific biochemical substances contained in the liquid sample and the constituents of a reagent contained in the dry-type chemical analysis film. Light is thus irradiated to the dry-type chemical analysis film, and the optical density is determined. The optical density depends on how much of a reaction product was formed by the reaction between the liquid sample and the reagent in the dry-type chemical analysis film. Thereafter, a calibration curve, which is created in advance and which represents the relationship between the optical densities and the concentrations of the specific biochemical substance in liquid samples, is used in order to determine the concentration (i.e., the content) or the activity value of the biochemical substance in the liquid sample from the optical density, which has been determined.
The dry-type integral multi-layer chemical analysis film described above comprises a substrate, which is constituted of an organic polymer, and at least a single reagent layer containing a reagent. The dry-type integral multi-layer chemical analysis film should preferably be provided with a spreading layer, which is overlaid upon the reagent layer. The dry-type integral multi-layer chemical analysis film is formed as a dry-type chemical analysis film piece having a predetermined shape, e.g., a square shape or a rectangular shape. Such that the operations using the dry-type chemical analysis film pieces may be carried out automatically, each of the dry-type chemical analysis film pieces takes on the form of a chemical analysis slide, which comprises organic polymer frames and the dry-type chemical analysis film piece sandwiched between the frames. Also, the inventors proposed a technique for loading a plurality of dry-type frameless chemical analysis film pieces directly into a cartridge, accommodating the cartridge in a film feeding device in a biochemical analysis system, taking the dry-type frameless chemical analysis film pieces out of the film feeding device one after another, and subjecting the dry-type frameless chemical analysis film pieces to a measurement one after another.
A technique for accommodating and feeding out dry-type chemical analysis films is disclosed in, for example, U.S. Pat. No. 4,151,931. With the disclosed technique, a plurality of dry-type chemical analysis films are stacked and accommodated in a cartridge having a take-out opening, which is formed at a top end of the cartridge and is open to a side surface of the cartridge. The dry-type chemical analysis film located at the top position is pushed out of the cartridge by a push-out blade, which is operated horizontally. In this manner, the dry-type chemical analysis film is fed into an analysis system. A support member for supporting the dry-type chemical analysis films is located at the bottom of the cartridge such that the support member can be moved only upwardly by a ratchet mechanism. The support member is moved upwardly by the operation of a plunger from below and is thus successively urged towards the take-out opening.
Also, a different technique for feeding out dry-type chemical analysis films is disclosed in, for example, U.S. patent application Ser. No. 08/253,607 and European Patent Publication No. 304,838. With the disclosed technique, dry-type chemical analysis films accommodated in a cartridge are pushed towards a take-out opening by a push member, which is urged by a spring (serving as an urging means). In this manner, the dry-type chemical analysis films are taken out of the take-out opening one after another.
However, when a cartridge, in which the dry-type chemical analysis films are stacked and accommodated, is stored or conveyed before being loaded into a biochemical analysis system, or when the cartridge is taken out of the biochemical analysis system and processed for maintenance, or the like, after being loaded into the biochemical analysis system, it often occurs that the cartridge falls and strikes against the floor, or the like, or is subjected to other impacts. In such cases, with the conventional cartridges described above, the problems occur in that the dry-type chemical analysis films accommodated in the cartridge are disturbed, turned over, or subjected to an excessive pushing force. As a result, adverse effects occur upon the operation for taking the dry-type chemical analysis film out of the cartridge and the measurement operation. In particular, the aforesaid problems occur markedly in cases where the cartridge accommodates therein a plurality of dry-type chemical analysis film pieces, which are curved and deformed and which exhibit a high resilience in the thickness direction when they are stacked.
Specifically, with the cartridge for dry-type chemical analysis films, wherein the urging of the push member provided with the ratchet mechanism is carried out by the insertion of the plunger, because of the ratchet mechanism, the push member can smoothly move in the direction, that pushes the dry-type chemical analysis films, but cannot move reversely. Therefore, in cases where the cartridge falls and strikes against the floor, or the like, with the side opposite to the take-out opening facing down, the push member does not move, and no problem occurs. However, in cases where the cartridge falls and strikes against the floor, or the like, with the side of the take-out opening facing down, the push member moves towards the take-out opening and locks the dry-type chemical analysis films in the pushed state. Therefore, there is the risk that the operation for taking the dry-type chemical analysis films out of the take-out opening one after another cannot be carried out smoothly due to the action of the excessive pushing force.
With the cartridge, wherein dry-type chemical analysis films are always pushed towards the take-out opening by the push member urged by the urging means, such as a spring, in cases where the cartridge falls and strikes against the floor, or the like, with the side of the take-out opening facing down, the push member moves in the direction, that compresses the dry-type chemical analysis films, and thereafter the push member returns to the original position. Therefore, in such cases, no problem occurs. However, in cases where the cartridge falls and strikes against the floor, or the like, with the side opposite to the take-out opening facing down, the push member moves in the direction heading away from the take-out opening due to deformation of the urging means, and the dry-type chemical analysis films are released from the pushing force. As a result, the dry-type chemical analysis films are disturbed. Also, if a space larger than the width of the dry-type chemical analysis films is formed, there is the risk that the dry-type chemical analysis films become upright or are turned over. In such cases, the dry-type chemical analysis films cannot be accurately taken out of the take-out opening one after another. Also, if the dry-type chemical analysis films, which have been turned over, are taken out and subjected to the operation for measurement, the measurement cannot be carried out.